National Instruments 372139B-01 Automobile User Manual


 
Chapter 6 Automotive Diagnostic Command Set API for C
Automotive Diagnostic Command Set User Manual 6-20 ni.com
Return Value
The return value indicates the function call status as a signed 32-bit integer. Zero means the
function executed successfully. A negative value specifies an error, which means the function
did not perform the expected behavior. A positive value specifies a warning, which means the
function performed as expected, but a condition arose that may require attention.
Use the
ndStatusToString function to obtain a descriptive string for the return value.
Description
ndDiagnosticService is a generic routine to execute any diagnostic service. The request
and response messages are fed unmodified to the
dataIn input and retrieved from the
dataOut output, respectively. No interpretation of the contents is done, with one exception:
The error number is retrieved from a negative response, if one occurs. In this case, an error is
communicated through the return value.
All specialized diagnostic services call
ndDiagnosticService internally.